In the process automation industry, object linking and embedding for process control (OPC) provides a standard for communicating with field devices. This standard allows for accessing process data, alarms, events, and historical process data. In a typical monitoring and control network, one or more servers are equipped with the OPC Server application which receives field device data and stores the data in volatile memory. This data is constantly being updated through polling functions initiated by the process control server or by a predetermined reporting cycle that the field devices follow to report the status of the I/Os (Inputs/Outputs) and field devices. The addressing information needed to access the field devices is stored in the process control server's tag database. The server tag database encapsulates the physical field device addressing into a simple text-based tag that is accessible by any clients with access to the network. The server tag database is specific to the types of field devices used in an application. This database requires considerable configuration efforts.
A client computer 108 is typically equipped with a Human Machine Interface (HMI) application that is used to visualize and interact with the field devices using symbolic images and standard windows widgets (e.g. listbox, textbox, radio button, checkbox). The HMI contains programs/drivers capable of communicating with any process control server accessible locally on the same computer or from the network. The HMI application's tag database is configured with the process control server tags that are referenced on the graphic pages. The process control server reports changes in the tag values to the HMI application, which then updates the appropriate graphical element. The HMI tag database is specific to the HMI and its graphics. This database also requires considerable configuration efforts.
One common method of displaying real-time server tag information on an HMI graphic consists of first adding a tag to the HMI tag database that references the process control server tag. Then a display element is added to the graphic (e.g. Textbox). Finally, the real-time display of that element is associated with the appropriate HMI tag database tag. The effort required to configure an HMI display and edit a large server tag database is considerable and error prone. Accordingly, an efficient device and method are needed for displaying and editing real-time server tag data without requiring the explicit configuration of the HMI tag database.